Tree of life reveals insights on plant variation

CEED member Roberto Salguero-Gómez manages a plant database called COMPADRE that brings together the life histories of over a thousand plant species. In a sense, it’s a window on the ‘tree of life’ (see the story in this issue). Now Salguero-Gómez and colleagues have demonstrated the value of this window by using COMPADRE to explain the worldwide variation in plant-life histories. Amazingly, most of this variation can be explained by just two variables: how fast the plant grows and its reproductive strategy.

“The database includes demographic records of survival, growth and reproduction standardised into population matrix models,” says Salguero-Gómez. “It’s a rich data resource for anyone studying plants, and will allow researchers to address important questions in the fields of conservation biology, ecology and evolution.”

The identification of patterns and underlying mechanisms governing the wide array of life history strategies across the tree of life is one example of this. Understanding these patterns is of vital importance to our prediction of population persistence, extinction and diversification.

“Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood,” explains Salguero-Gómez. “We have used demographic data from COMPADRE for 418 plant species from all four corners of the globe to examine how growth form, habitat and phylogenetic relationships structure plant life histories.”

The plant species being considered covers most of the spectrum of plant life on the planet, from tiny annual herbs to giant trees that live for many centuries, even millennia.

“We found that life history strategies of these 418 plant species – very different species from all over the world – can be explained by an axis representing the ‘pace of life’ and another representing their wide range of reproductive strategies,” says Salguero-Gómez. “Our framework predicts responses to perturbations and long-term population performance, thus showing great promise as a predictive tool for understanding plant population responses to environmental change.”

Understanding how life history strategies are structured is fundamental to our understanding of the evolution, abundance and distribution of species. These findings suggest that fast-slow growth strategies and reproduction strategies are a general organising principle in the plant kingdom. The findings have similarities with how life history strategies are structured in mammals, birds and reptiles suggesting they are central for how life is organised on planet Earth in general.